bug#51727: add an optional flag to -P to disable JIT

[Paul Eggert]

On 11/10/21 04:11, Carlo Arenas wrote:
> On Tue, Nov 9, 2021 at 4:40 PM Paul Eggert <eggert@cs.ucla.edu> wrote:

> its main use, for me at least, was to
> actually see how much time I am saving by using jit, and to avoid
> hitting buggy jit code paths I might have introduced myself ;), which
> is what the commit message kind of implies.

This sounds esoteric enough that we needn't support/document it for 
'grep' users. (Their lives are complicated enough already....)


> enable extended
> mode, so that users that have really complex expressions can write
> them as multiline strings with comments,

This wouldn't be just a PCRE thing; even ordinary BREs and EREs could 
benefit from being able to have multiline regexps, in which a newline 
means "|". The GNU regular expression compiler supports this. Also, we'd 
need to disable grep's ordinary activity of reordering and removing 
duplicates in regular-expression patterns (in the current syntax where a 
newline always starts a new pattern). So I expect this wouldn't be a new 
-P suboption; it'd be a more-general option that applies to all regexp 
syntax options (though it'd be a no-op for -F).


> and one to tell PCRE to skip
> the UTF-8 validation if your content is know to be safe

... and let grep dump core (or worse) otherwise? I'm not sure I would 
like to to head in that direction....